Optical splitting device, optical multiplexing device and method, and optical add-drop multiplexer

Abstract

Embodiments of the present invention provide an optical splitting device, an optical multiplexing device and method, and an optical add-drop multiplexer, which relate to the technical field of communications, and are invented for improving the performance and decreasing the cost. The optical splitting device includes a substrate, where an anti-reflective coating is disposed on an upper surface of the substrate and a filter membrane is disposed at a lower surface of the substrate; and further includes a light redirecting portion disposed opposite to the filter membrane. An optical signal is incident to the filter membrane at a first specified angle, a light wave of a first wavelength in the optical signal penetrates the filter membrane, so that the light wave of the first wavelength is separated from the optical signal.

What is claimed is: 
     
       1. An optical splitting device comprising:
 a substrate, wherein an anti-reflective coating is disposed on an upper surface of the substrate and a filter membrane is disposed at a lower surface of the substrate, wherein the substrate has an at least approximately constant thickness that separates the anti-reflective coating and the filter membrane, and wherein the anti-reflective coating and the filter membrane are parallel; and 
 a light redirecting portion disposed opposite to the filter membrane, wherein the anti-reflective coating is disposed between the light redirecting portion and the substrate, and wherein the light redirecting portion is spaced apart from the anti-reflective coating by a distance, 
 wherein the filter membrane is configured such that when an optical signal is incident to the filter membrane at a first specified angle, a light wave of a first wavelength in the optical signal penetrates the filter membrane such that the light wave of the first wavelength is separated from the optical signal, and a light wave other than the light wave of the first wavelength is reflected by the filter membrane to the light redirecting portion, 
 wherein the light redirecting portion is configured to enable the light wave reflected to the light redirecting portion to be incident to the filter membrane at a second specified angle, 
 wherein the filter membrane is configured such that when a light wave of a second wavelength in the optical signal penetrates the filter membrane, the light wave of the second wavelength is separated from the optical signal, 
 wherein the second specified angle is different from the first specified angle, 
 wherein the filter membrane is configured such that when the first specified angle is an incident angle at which the optical signal is incident to the filter membrane, the filter membrane allows the penetration of the light wave of the first wavelength, and 
 wherein the filter membrane is configured such that when the second specified angle is an incident angle at which the optical signal is incident to the filter membrane, the filter membrane allows the penetration of the light wave of the second wavelength. 
 
     
     
       2. The optical splitting device according to  claim 1 , wherein the optical splitting device comprises at least two light redirecting portions, and wherein the at least two light redirecting portions are disposed at intervals. 
     
     
       3. The optical splitting device according to  claim 1 , wherein the optical splitting device comprises a number of light redirecting portions, and wherein the number of light redirecting portions is selected from a group consisting of 1, 3, and 7. 
     
     
       4. The optical splitting device according to  claim 1 , wherein the light redirecting portion comprises a reflecting mirror or a reflective coating. 
     
     
       5. The optical splitting device according to  claim 4 , wherein the reflecting mirror or the reflective coating is disposed at a specified angle opposite to the filter membrane. 
     
     
       6. The optical splitting device according to  claim 1 , wherein the light redirecting portion comprises at least three light redirecting portions, wherein each of the at least three light redirecting portions is at a specified angle with respect to the filter membrane, and wherein the specified angles of the at least three light redirecting portions are different from each other. 
     
     
       7. An optical multiplexing device comprising:
 a substrate, wherein an anti-reflective coating is disposed on an upper surface of the substrate, and a filter membrane is disposed at a lower surface of the substrate, wherein the substrate has an at least approximately constant thickness that separates the anti-reflective coating and the filter membrane, and wherein the anti-reflective coating and the filter membrane are parallel; and 
 a light redirecting portion disposed opposite to the filter membrane, wherein the anti-reflective coating is disposed between the light redirecting portion and the substrate, and wherein the light redirecting portion is spaced apart from the anti-reflective coating by a distance, 
 wherein the filter membrane is configured such that when a light wave of a first wavelength is incident to the filter membrane and penetrates the filter membrane, a light wave of a second wavelength is incident to the filter membrane at a third specified angle and penetrates the filter membrane, 
 wherein the light wave of the second wavelength penetrating the filter membrane is incident to the light redirecting portion, 
 wherein the light wave of the second wavelength is incident to the filter membrane at a fourth specified angle by the light redirecting portion, 
 wherein the filter membrane is configured such that when the light wave of the second wavelength incident to the filter membrane at the fourth specified angle is reflected by the filter membrane and encounters the light wave of the first wavelength penetrating the filter membrane that multiplexing of the light wave of the first wavelength and the light wave of the second wavelength is implemented, 
 wherein the third specified angle is different from the fourth specified angle, and 
 wherein the filter membrane is configured to allow penetration of the light wave of the second wavelength when the third specified angle is an incident angle at which the light wave of the second wavelength is incident to the filter membrane. 
 
     
     
       8. The optical multiplexing device according to  claim 7 , wherein the optical multiplexing device comprises at least two light redirecting portions, and wherein the at least two light redirecting portions are distributed at intervals. 
     
     
       9. The optical multiplexing device according to  claim 7 , wherein the optical multiplexing device comprises a number of light redirecting portions, and wherein the number of light redirecting portions is selected from a group consisting of 1, 3, and 7. 
     
     
       10. The optical multiplexing device according to  claim 7 , wherein the light redirecting portion comprises a reflecting mirror or a reflective coating. 
     
     
       11. The optical multiplexing device according to  claim 10 , wherein the reflecting mirror or the reflective coating is disposed at a specified angle opposite to the filter membrane. 
     
     
       12. The optical splitting device according to  claim 6 , wherein each of the anti-reflective coating and the filter membrane runs along an entire length of the substrate. 
     
     
       13. The optical multiplexing device according to  claim 7 , wherein the light redirecting portion comprises at least three light redirecting portions, wherein each of the at least three light redirecting portions is at a specified angle with respect to the filter membrane, and wherein the specified angles of the at least three light redirecting portions are different from each other. 
     
     
       14. The optical multiplexing device according to  claim 13 , wherein each of the anti-reflective coating and the filter membrane runs along an entire length of the substrate. 
     
     
       15. An optical splitting method comprising:
 receiving an optical signal at a substrate, wherein an anti-reflective coating is disposed on an upper surface of the substrate and a filter membrane is disposed at a lower surface of the substrate, wherein the substrate has an at least approximately constant thickness that separates the anti-reflective coating and the filter membrane, wherein the anti-reflective coating and the filter membrane are parallel, wherein a light redirecting portion is disposed opposite to the filter membrane, wherein the anti-reflective coating is disposed between the light redirecting portion and the substrate, and wherein the light redirecting portion is spaced apart from the anti-reflective coating by a distance; 
 enabling the optical signal to be incident to the filter membrane at a first specified angle; 
 utilizing the filter membrane to enable a light wave of a first wavelength in the optical signal to penetrate the filter membrane such that the light wave of the first wavelength is separated from the optical signal and a light wave other than the light wave of the first wavelength in the optical signal is reflected by the filter membrane to the light redirecting portion; 
 utilizing the light redirecting portion to enable the light wave that is reflected by the filter membrane to the light redirecting portion to be incident to the filter membrane at a second specified angle; and 
 utilizing the filter membrane to enable a light wave of a second wavelength in the optical signal to penetrate the filter membrane such that the light wave of the second wavelength is separated from the optical signal, 
 wherein the second specified angle is different from the first specified angle, 
 wherein the first specified angle is an incident angle at which the optical signal is incident to the filter membrane when the filter membrane allows the penetration of the light wave of the first wavelength, and 
 wherein the second specified angle is an incident angle at which the optical signal is incident to the filter membrane when the filter membrane allows the penetration of the light wave of the second wavelength. 
 
     
     
       16. The optical splitting method according to  claim 15 , wherein utilizing the light redirecting portion to enable the light wave that is reflected by the filter membrane to the light redirecting portion to be incident to the filter membrane at the second specified angle comprises reflecting, by a reflecting mirror or a reflective coating, the light wave reflected by the filter membrane to the light redirecting such that the light wave reflected by the filter membrane to the light redirecting portion is incident to the filter membrane at the second specified angle. 
     
     
       17. The optical splitting method according to  claim 15 , wherein each of the anti-reflective coating and the filter membrane runs along an entire length of the substrate, wherein the light redirecting portion comprises at least three light redirecting portions, wherein each of the at least three light redirecting portions is at a specified angle with respect to the filter membrane, and wherein the specified angles of the at least three light redirecting portions are different from each other. 
     
     
       18. An optical multiplexing method comprising:
 receiving a light wave of a first wavelength and a light wave of a second wavelength at a substrate, wherein an anti-reflective coating is disposed on an upper surface of the substrate and a filter membrane is disposed at a lower surface of the substrate, wherein the substrate has an at least approximately constant thickness that separates the anti-reflective coating and the filter membrane, wherein the anti-reflective coating and the filter membrane are parallel, wherein a light redirecting portion is disposed opposite to the filter membrane, wherein the anti-reflective coating is disposed between the light redirecting portion and the substrate, and wherein the light redirecting portion is spaced apart from the anti-reflective coating by a distance; 
 enabling the light wave of the first wavelength to be incident to the filter membrane; 
 enabling the light wave of the second wavelength to be incident to the filter membrane at a third specified angle; 
 utilizing the filter membrane to enable the light wave of the first wavelength to penetrate the filter membrane and to enable the light wave of the second wavelength to penetrate the filter membrane and be incident to the light redirecting portion; 
 utilizing the light redirecting portion to enable the light wave of the second wavelength incident to the light redirecting portion to be incident to the filter membrane at a fourth specified angle; and 
 utilizing the filter membrane to enable the reflected light wave of the second wavelength that is incident at the fourth specified angle to encounter the light wave of the first wavelength penetrating the filter membrane to implement multiplexing of the light wave of the first wavelength and the light wave of the second wavelength, 
 wherein the third specified angle is different from the fourth specified angle, and 
 wherein the third specified angle is an incident angle at which the light wave of the second wavelength is incident to the filter membrane when the filter membrane allows the penetration of the light wave of the second wavelength. 
 
     
     
       19. The optical multiplexing method according to  claim 18 , wherein utilizing the light redirecting portion to enable the light wave of the second wavelength incident to the light redirecting portion to be incident to the filter membrane at the fourth specified angle comprises reflecting, by a reflecting mirror or a reflective coating, the light wave of the second wavelength incident to the light redirecting such that the light wave of the second wavelength is incident to the filter membrane at the fourth specified angle. 
     
     
       20. The optical multiplexing method according to  claim 18 , wherein each of the anti-reflective coating and the filter membrane runs along an entire length of the substrate, wherein the light redirecting portion comprises at least three light redirecting portions, wherein each of the at least three light redirecting portions is at a specified angle with respect to the filter membrane, and wherein the specified angles of the at least three light redirecting portions are different from each other.